3 Doses Kills Fleas, Flea Eggs & Larvae and Chewing Lice Fast Acting Long-Lasting Waterproof Use Only on Cats weighing over 1.5 lbs and 8 weeks or older Kills all stages of ticks including those that may transmit Lyme disease. PetAction Plus for Cats contains the active ingredients fipronil and (S)-methoprene that effectively target fleas, ticks, and chewing lice. PetAction Plus for Cats is fast-acting, long-lasting, waterproof, and easy to use. PetAction Plus for Cats remains effective even after bathing, water immersion, or exposure to sunlight. PetAction Plus for Cats can also be used for the treatment and control of flea, tick, and chewing lice infestations on breeding, pregnant and lactating queens.